The Canon Macro Twin Lite MT-24EX Flash is an extremely flexible and very easy to use macro flash.
As the name implies, the Canon Macro Twin Lite MT-24EX Flash is primarily suited to macro flash photography. The close subject distances inherent in macro photography require narrow aperture openings to obtain adequate DOF (Depth of Field). These narrow openings require lots of light - or very slow shutter speeds. Slow shutter speeds dictate the use of a very stable tripod - and a motionless subject.
The other option - lots of light - is generally provided by a flash. The burst of light provided by a flash is generally fast enough (provided that any ambient light is overcome) to freeze both subject and camera motion.
Although there are many ways to utilize a flash for macro photography lighting, I don't think any are as easy to use and as flexible as the Canon Macro Twin Lite MT-24EX Flash.
Upon opening the Canon Macro Twin Lite MT-24EX Flash box, I was pleasantly surprised to find a nice zippered nylon case made to fit this uniquely designed flash. The flash heads, control unit and wires all get their own little padded sections.
The flash mount ring attaches directly to the objective end of the Canon EF 50mm f/2.5 Macro Lens, Canon EF 100mm f/2.8 Macro USM Lens or Canon MP-E 65mm 1-5x f/2.8 Macro Lens. Mounting the Canon Macro Twin Lite MT-24EX Flash on the Canon EF 180mm f/3.5 L USM Macro lens requires the optional modestly-priced Canon Macro Lite Adapter 72C.
A button on the flash mount ring releases four catches and allows it to slide over the end of the lens (after the lens cap and hood are removed). The lens cap and hood can be reattached to the flash mount ring. The flash mount ring can rotate to and lock in the position you wish by pressing/releasing the button.
Two small flash heads (marked A and B for their respective IDs) mount to the flash mount ring (thus its name). They slide and snap into mini flash shoes. A button press on each individual flash head mount is required to release the heads.
Each flash head can be individually tilted in and out (friction-held with click stops). As well, each head can be individually rotated around the ring (requires a release button to be held in). And again, the flash mount ring itself can be rotated - rotating both flash heads simultaneously.
The flash heads do not even need to remain in their mounts. Remove one or both and position them exactly where you want them.
The Canon Macro Twin Lite MT-24EX Flash's generous range of adjustments are well thought out and very easy to change.
As can be seen in the picture below, the Canon Macro Twin Lite MT-24EX Flash's heads are coil-wired to a control unit about the size of the Canon 550EX Flash without the head attached.
The Canon Macro Twin Lite MT-24EX Flash contains most of the features found on the Canon 550EX Flash including FEC (Flash Exposure Compensation), FEB (Flash Exposure Bracketing), FP (High Speed Synch) and flash output ratio (8:1 to 1:8 in 13 1/2 stop steps).
With a set of dedicated buttons, the ratio feature is very easy to use. It can control flash IDs A, B (the built-in flash heads) and C. The Canon Macro Twin Lite MT-24EX Flash can control slaves flashes set to any of these IDs as well. A custom function lets slave flashes with an A or B ID fire at the same ratio as the built-in flashes.
A more typical use for a slave flash is an ID C flash controlling the background light. Since light fall-off from the main flash heads used with narrow apertures often renders a background black, a slave flash can be utilized to add light behind the subject. Individual flashes can be optionally turned off as well.
The Canon Macro Twin Lite MT-24EX Flash supports full E-TTL exposure as well as M (Manual) for full control.
The Canon Macro Twin Lite MT-24EX Flash's build quality is good - and similar to Canon's Speedlite Flashes. Also like the other Speedlite flashes, the Canon Macro Twin Lite MT-24EX Flash is powered by 4 AA Batteries. A Power Off/On/SE (Save Energy) button allows the Macro Flash to go into sleep mode after 90 seconds.
Macro photography with magnifications approaching 5x starts yielding a very dark viewfinder. The Canon Macro Twin Lite MT-24EX Flash can produce a 1 second modeling flash to aid in focusing and flash effect preview. Pressing the DOF (Depth of Field) Preview button fires the modeling lights.
As with any multiple flash setup, double shadows can easily creep into Canon Macro Twin Lite MT-24EX Flash pictures. Controlling the output ratios and positions of the flash heads is the answer to this problem.
For general macro photography, I found the MT-24ex's very small flash heads to create somewhat harsh lighting. Having been using a relatively large light source for my macro photography, a small softbox, I was not overly found of the look created by the Canon Macro Twin Lite MT-24EX Flash. As the subjects become smaller and closer, the Twin Lite results look better to me. The size of the flash compared to the close proximity and small subject size results in a softer appearing light source. That said, I haven't heard anyone else talking about the harshness of the Canon Macro Twin Lite MT-24EX Flash's light.
When using a super macro lens such as the Canon MP-E 65mm 1-5x Macro Lens, the Canon Macro Twin Lite MT-24EX Flash becomes almost mandatory. Working distances on this lens become so small that even the tiny flash heads on the MT-24ex can get in the way. The MT-24 is the ideal companion to the MP-E.
The Canon Macro Twin Lite MT-24EX Flash is an incredibly flexible, portable and powerful flash that makes macro flash lighting easy (well, almost).